Because the daily lectionary parses out the reading of the New Testament epistles as it does, we created this page as a single resource to explain the origins and categorizing of all the various letters.
The majority of the 21 books in this final category were written as letters to specific audiences, with the intention that the written scroll would be delivered to the audience and read aloud. Even though some of the 21 books don’t meet that criteria, they are commonly called “epistles” or “letters."
Ancient Authors' Pseudepigraphic Writing
"At present, we see indistinctly, as in a mirror; but then face to face." (1 Corinthians 13:12)
Uncertainty about authorship of some books of the Bible can be attributed to pseudepigraphic writing, aka, "reverse plagiarism." In ancient times, it was common for an unknown author to claim that their work was written by someone better-known. Such claims would give these works larger audiences and greater authority. (As examples, it seems unlikely that David wrote all of the Book of Psalms or that Solomon wrote the Book of Proverbs.) This practice is hard for us to accept, since in our time, it is more common for authors to take credit for the words of others!
For modern biblical scholars, the problems of attribution plague many of the epistles. 20 of the 21 epistles identify an author, and 15 claim to be written to specific audiences. Are those attributions true, or were some of these letters written by other people—perhaps by followers of the claimed author, perhaps decades later, perhaps at cross purposes to what the claimed author would have written? Sometimes, scholars agree on the conclusions reached; sometimes, they do not.
No matter how these books were written, edited, redacted, and promulgated, the early Church determined that each was created by the guidance of the Holy Spirit as the inspired Word of God, worthy of inclusion in the biblical canon.
There are a lot of different ways to categorize the 21 epistles. For simplicity, we divide them into the three major categories used by the Bible.
Category I: Pauline Epistles
"I can do all things through God who strengthens me." (Philippians 4:13)
Traditionally, the authorship of the first 13 epistles listed in the Bible have been attributed to St. Paul the Apostle. They are arranged in order of length, from longest to shortest. (There are exceptions so that 2 Corinthians, 2 Thessalonians, and 2 Timothy follow directly after 1 Corinthians, 1 Thessalonians, and 1 Timothy.) The Pauline epistles are often broken down into additional subcategories by their content and/or by the theories of modern scholars about their actual authorship.
Authentic Pauline Epistles
A consensus of scholars believes that Romans, 1 Corinthians, 2 Corinthians, Galatians, Philippians, 1 Thessalonians, and Philemon were written by St. Paul the Apostle himself, to the audiences to which the letters say they were addressed. These seven letters have similarities in themes, language, and style. They were most likely written in the 50s, starting with 1 Thessalonians and perhaps ending with Romans.
"We walk by faith, not by sight." (2 Corinthians 5:7)
Disputed Pauline Epistles
The other six Pauline epistles are sometimes called the Disputed Pauline epistles, because there is not a consensus on whether Paul wrote them. When scholars question Paul's authorship of a particular letter, they almost always question the intended audience of the letter, positing that the letter was intended for a more universal audience. The Disputed Pauline epistles are often broken into two groups of 3 letters each, based on the level of scholarly disputation.
"We are God's handiwork, created in Christ Jesus to do good works." (Ephesians 2:10)
Deutero-Pauline Epistles
Most contemporary scholars think that Ephesians, Colossians, and 2 Thessalonians were not written by Paul nor addressed to the audiences named. Yet, a significant number of scholars argue for Pauline authorship of these letters, especially Colossians. These three epistles share many thematic, linguistic, and grammatical features of the 7 Authentic Pauline epistles, but there are enough changes in perspective, theology, and emphasis to raise legitimate questions about whether Paul is the author.
If Paul did not write these letters, who did? Those scholars who dispute the traditional authorship believe these letters were written by followers of Paul perhaps a generation later, 80 - 100 AD.
Pastoral Epistles
Since the 18th century, the remaining Pauline letters—1 Timothy, 2 Timothy, and Titus—have been called the Pastoral epistles, because they concern leadership within the Church. The letters claim to be written by Paul to two specific men charged with leading specific Christian communities. Most scholars believe that the concerns in these letters—and the discussion of organized leadership structures within local church communities—refer to a time in the Church probably long after Paul's martyrdom in the 60s.
"All Scripture is God-breathed and is useful for teaching." (2 Timothy 3:16)
Category II: Hebrews
"Let us confidently approach the throne of grace." (Hebrews 4:16) Cathedral of Lancaster, England (credit: Lawrence, OP)
Despite its title, the consensus of biblical scholars is that Hebrews is not a letter, it was not written by Paul, nor was it written to an exclusively Hebrew-speaking audience.
This book is a genre unto itself. It is a theological treatise intended for an audience of people familiar with the Jewish scriptures, probably for the Jewish Christians in both Judaea (who like spoke both Hebrew and Greek) and the diaspora (who likely spoke Greek but not Hebrew). The letter is written in the most eloquent Greek of the New Testament.
Category III: The "Catholic" Epistles
Although the 7 remaining books (James, 1 Peter,2 Peter, 1 John, 2 & 3 John, and Jude) are introduced as letters, most seem to have been written to universal (i.e., catholic) audiences, rather than being sent to a specific community or person. 2 John is addressed "to the chosen Lady and to her children whom I love in truth" and 3 John is addressed to someone named "Gaius," but they are included here to follow directly after the much-longer 1 John.
"Cast all your cares on the Lord, because he cares for you." (1 Peter 5:7)